Known powered rail vehicles include one or more powered units and one or more cars. The powered units supply tractive force to propel the powered units and cars. The cars hold or store goods and/or passengers, and may be non-powered units, meaning rail vehicles incapable of self-propulsion. For example, some known powered rail vehicles include a rail vehicle consist (group of vehicles mechanically linked to travel together) having locomotives and cars for conveying goods and/or passengers along a track. Some known powered rail vehicles include several powered units. For example, the systems may include a lead powered unit, such as a lead locomotive, and one or more trailing or remote powered units, such as trailing or remote locomotives, that are located behind and coupled with the lead powered unit or behind rail cars. The lead and trail or remote powered units supply tractive force to propel the system along the track.
The tractive force required to convey the powered units and cars along the track may vary during a trip. For example, due to various parameters that change during a trip, the tractive force that is necessary to move the powered units and the cars along the track may vary. These changing parameters may include the curvature and/or grade of the track, speed limits and/or requirements of the system, and the like. As these parameters change during a trip, the total tractive effort, or force, that is required to propel the system along the track also changes.
Some known rail vehicles provide for the automatic control of the tractive effort provided by at least some of the powered units in the rail vehicle. For example, a first powered unit may automatically control throttle settings and the like for one or more other powered units in the same rail vehicle. The first powered unit may transmit directions to the other powered units over a wireless connection or a wired connection. Due to wireless interference, changes in the terrain (e.g., tunnels and/or curves over or around hills, mountains, rock walls or cliffs, or within valleys), and/or physical damage to wired connections, the communication of directions from the first powered unit to the other powered units can be interrupted. When such interruptions are detected, the first powered unit may switch to a manual state for safety reasons, which requires a human operator to take over control of the powered units.
Some of the interruptions in the communication may be temporary and not permanent. For example, a cause of a communication interruption between powered units may include the rail vehicle entering into a tunnel or valley. However, the rail vehicle may not remain in the tunnel or valley indefinitely (e.g., the rail vehicle may eventually exit the tunnel or valley). But, the first powered unit may have switched to manual control during the temporary communication interruption so that the operator is manually controlling the rail vehicle. Such a switch to manual control may be unnecessary and can reduce fuel efficiency of the rail vehicles as well as affect train handling.